Note: Descriptions are shown in the official language in which they were submitted.
I~ACl~G~20UND OF THE INVENTION
The pr0sent ln~rention relate~ to expandlng bello~
provided with annular exp~n~l~ n~ corrllgation:~ o i` dete~mined
inner and outer dia~eter~3 wlth, inside each corrugatior
anrlular reinforcin~ por tions adapted to b~ introclucedg
each~ into the tubular part of i~ner diameter o:f the bel-
low.e and b~ as~clDbled as a re~ nfo~cing rimg, a:3 well
meanE~ for blocking th~ ar~ular portio~ p æach ~nrlular
re:Lnf`orclng partion ha~rlng an i:llnE3r a;rc and an outer arc
10 of which the chords wh~ ch subtend them ha~e lengths at
least e~ual to the in~er diameter of` the bellow3,.
Such expF~nc~ g bells>ws are alre~dy ]CllOW:n~9 particular-
1~ by ~rench Pate~l; N~ 451 3279
Conventional axp~n~l~n~ b~llow~ can only with~tand a
limited inner and/or outer pre~sllre of u~e.
To incr~a~ thi~ pr*~ure o~ u~e, it has al-
ready b~cn propo~ed either to incre~se the thickness of
the wall of the bellows~ or to incr~a~e the number of tha
~in.e wall~ constituting the bello~ In the ~ormer ca~e,
it ~ the li~e duration o~ the bellows which limlts the
thic~nes~ thereof~ in~er3e1~ proportional to thi~ life
duration. I~ the latter case, it i~ the pheno~ena cf ~lld~
between wall~ which limit the numbar of the fi~9 ~Pll~ which
may be a~soci~ted.
~ urth0rmore 1 a~ f~r as the inn~ li~iting press~re
alone is concsrnad, it has already been proposed to rein-
force the corr~gation~ o~ th~ bellows by outer reinforceme~ts~
.i, ~
5~
1~e latter may be oo~stit~ted by two annular piec~
di~po~d, aftsr manu:facture I b~twe~rl two corrugation~ ~nd
mechanlcally s~onnected togatherO
~ Iowe~er, wh~n the bellow~ are manufas~tured by hydro~
forming7 it is pref`erably the ma~uf'acturing mould~ the~
re2s w~ich3 held in place a~ter m nuf~cture ~ serve aa
monoblt)c ~uter rel:nf-orcl~g me n~sO
If` it i~ de~ired to rainf`orce eXp~n~ bellow so
that they withstand higher out~3id~ pressur~ therefor~3
10 wit~ th~ aid. of` i~e:~ rein:~orce~ nt:3 ~ i t iL~ imperati~e to
n~ount the latter after manu~acture of' the bellows ~ In
:fact, the formation of the corrugation~s o:f the b~llows in
t~he c~urse o:f manu~aoture; ln other words the ex~an:3ion cf
the starting tube, make~; it imposslble to arr~nge in~ide
it any reinrorcement which would be holl~;ed in one of the
corrugations and would have an outer diameter forclbly
greater than ths inn0r diameter o~ ~he corrugation~ i.e.
t~e diam~ter of the 3tarti~g tube.
A~ far a~ the eXpQn~;ne bellows of French Pate~t
N 451 327 are concer~ed, they do i~dsed compri~e inner
pieCeff which may be mounted arter manu~ac$ure of the bellows.
Howe~er~ there is a large numb~r o~ piece~ in the3e
bellow~ and they are a~embled by ~crews a~d pin~ Thi~
re~ults in a mechanical weaknas~ o~ these piece~ which can
therefore not per~orm a function o~ mechanical reinforce-
~ent o~ the bellow~ 9 ~he~ the latter arc ~ub~ected to a
considerabl~ out~lde pressure. The plece~ of the~e bellow$
-- 2
~5~7
ar~ in fact int¢nded only to limit th~ longitudinal co~-
traction of the bello~. Strlctly speaki~gg they do not
perform a role of reinforcement.
It i~ therefore an object of the pr¢sent invention to
o~ercome the drawbacks of such bellow~.
SUMMARY OF THE INVENTION
To this end, the in~ention rel~*es *o bell3ws Or the
type mentioned herelnabo~e~ characterized in that tha inner
ch~r~ ~ a~ lea t one of th~ annular portion~ i~ at lea~t
a~ large as the o~ter chord thereof.
The bellow~ o~ th~ inventlon therefore compri~e rei~-
forcing portion~, of very li~ltsd numbar7 which buttres~
on one ~nother a~d remain assembled under the effect of
tha outslde pres~ur~ 9 wlthout other means ~uch a~ the
~crew~ and pins of the prior art.
In a preferred embodiment of the b~llow~ of the inven-
tion~ at least on~ of th~ annular reinforcin~ portions
ha~ an i~er chord and an outer chord which are parallel
a~d o~ the same length.
In this latter ca~ie~ it i~ advanta~eou~ to provide a
rein:f`orcillg ring comprising two identical an3lular por-tions
eac~ having an inn~r chord and an outer chord of which the
~agittae merge and o:f' whlch the di~tarlc:e~ to the ax~ ~ of
th~ bellow~ are eqtlal9 the le~th o~ the inn~r e:hord being
~;lightly greate~ than one *h~ rd of tk~ length o:P the~ oute~
chDrd .
3S~37
BRIEF DESCRIPTION OF T~E DRAWIN&S
The in~0ntio~ will be ~ore readlly understood o~ rea~
ding the fO11DWing de~cription with reference to the acco~-
pan~i~g dra~ings, in w~ich s
Fig. 1 shDws a radial vlew of on~ of the corrugation~
of the bellows with a first a~nular reinfor2ing portion,
be~or~ a~d afte~ introductlon.
Fig. 2 show~ an axial vlew o~ the cDrrugatlo~ of
Pigo 1.
Fig. 3 6how~ a radial ~lew o~ the corrugation with a
~cond a~nular r~in~orci~g portion/` id~ntical to the flr3t~
be~ore a~d after introductio~
Fig. 4 sh~ws an axial ~i~w of th~ corrugatlon o~
~ig. 3-
~ig. 5 show~ a radial vi~w of the corrugation, ~ith
a third an~ular sein~orci~g portion~ before and a~ter
introduction.
~ig. 6 show~ an axial view v~ the corrugation Or
Fig. ~-
Fig. 7 ~howY a radial view o~ the corrugatlo~, with
a f`ourth a~d last a~nulas~ rein~orcing portion~ identical
to th~ third, b~ore and after int~oductio~.
Fig. 8 show~ a~ axial vi~w of the corru~atio~ o~
igo 7 o
Fig. 9 ~hows a ra~ial view o~ th~ corrug~tion~ with
the inn~r rein~rcin~ ring and a blocking ring~ bsfor~
a~d aft0r introduction.
37
Fig. 10 ~how~ an a~ial vi~w of the corrugation of
Fig. 9-
Fig. 11 ~how3 a radial view, with a~ial half section9of the bello~s of the i~rention9 and
~ ig. 12 shows a radial ~iew, with axial half~section,
o~ the bellow~ ~r ~ig~ 11 9 with oute~ rein~orcing r.i~g~
DESCRIPTION OF A PRE~ER~ED EMBODIMENT O~ T~æ
lN v~ ON
Re~erring now to the drawin~s, th~ exp~n~7in~ bel~ow~
or ga~ket or equalizer~ ~ the in~ention, whish will be
de~cribed~ i~ a body 1 o~ general tubular form, of a~ 59
compri~in~ identical an~lu~ar radial e~pa~ding CorrUgationB
29 four in th~ pre~ent case although the in~ntio~ i~ not
limited to this number. The~ r~gularly spac~d-apart cor-
rugation~ ~orm a tubular part 3 of determined lnner diameter~
and a part 4 Or d*ter~ined outer diameter, gr~ater tha~
that of the l~r part 3. Th~e c~rrugationo were ob~ained,
for example r b~ hydroforming, which ls a process suf~i-
ciently well known to the man skilled in the art ~or it to
be unnQoessary to be de3crlbed h~re. 'rhe-~e corrugation
have radial ~ides9 sub~tantially at right angle~ *o the
a~is 5 o~ the bellows.
The compo ition~ i~troductio~ ~nd blockin~ o~ an in~er
rein~orcin~ ring associated ~lth one o~ the corrugatlo~ 2
w~ 11 now be dgscribed, lt bei~g under~tood that each cor~
rugation 2 is pro~ided with 5uch a ring~
The iD~er rein~orc~ng ring 6~ once a3~smbled tFigs.8
-- 5 ~-
5~33~
to 12), there~ore ha~ an annular ~orm o~ whlch the lnner
part 7 i~ htly thicker tha~ the outer part 8~ a narro-
wed cheek element 9~ o~ s~aller thlckne~s than the outer
part, cDnnecting the two lnner ~nd outer parts. T~e out~r
part 8 o~ the ring has sub~antially the same thickne3
as corrugation 2.
The rin~ 6 comprlse~ two pairs o~ identi~al annular
portlon6 (10, 11) and (12~ 13).
Each ~n~ ~ portion (10013) has a~ inner arc and an
outer arc. The chord~ ~hich ~ubtend these arc3 all ha~s a
length le~ than th~ dlameter o~ the inner tubular part 3.
I~ fact, it i~ nece~sary t~ be able to lntroduc~ thes~
a~ular portion~ therein. ~ore~Yer9 lt ~u~fice~ that tha
length o~ ~he~e chord~ b~ slightly le~ than thi~ inner
diam~ter.
Th~ annular portlon~ 10, 11 have~n inner arc 14 and
an outer arc 15 re~pecti~ely of the same radii a8 the
tubular parts 3, 4. These arc3 are ubte~ded by chords
which extend o~r the ~ame straight line. In other word3,
the two chord~ which 3ubt~nd the~e two arc~ have ~erged
s~gittae and their di~tances to the.axi3 5 of the bellows
are equal. The Qhord of the ~ nner arc 14 ha~ a le~gth
~ htly greater tha~ one third o~ the le~gth of the chord
Or the outer aro 15~ for a r~a~on whloh will appear herelw
nafter~ In other word~ this i~ner chord 1~ ~lightly lo~ger
than each Df the t~o adjacent port1on~ of the outer chordO
The annular portions 12, 13 have an inner arc 16 and
-- 6
3~
an s~ter aro 17 respectlvel~ o~ the ~ame radii as the t~-
bular parts 3, 4. T~le two chords which r~peotively ~ub-
tend these two arc~ are parallel and of the same length.
The length of th~ outer arc 17 of the portions 12, 13 i~
equal to the differe~ce between half the ci~cumferenc~ of
the outer tubular part 4 and the length of the outer aro
15 of thc portions 109 llc The length o~ the inner arc 16
of portions 12, 13 is equal to the dif~erence betwe~n half
the circumfer~nce of the inn~r tubular part 3 and the le~gth
Or the inner arc 14 of the portions 109 11.
The annular portion3 12, 1~ ha~e two plane~ o~ ~oin 18
19 perpendicular to their two chordR subten~l ng th~lr inn~r
and outer arcs 16 and 17, re~pecti~ely, which are adapted
to cooperate with the two portion~, co~pri~ed between the
two arc~ 14 and 15 9 0~ the two outer chord~ of the annular
portions 10, 11.
II1 the for~going de~cription, the thicknes~ of the
annular portions, mentioned abova~ ha~ o~ cour3e, been
disreg~rded.
Having described the annular por~io~ o~ the relnfor-
cin~ ring 6, we shall now describe the introduction thereQ~
lnto ths corrugation 2 of the hellow~
With four annular portions 10-13 available, the ~lrst
portion 10 is taken9 i~ltroduced a~ially (Fig. 1~ in-to the
tubular part 3 and s~id radially ~Fig. 2~ i~to corrugation
2, so that the two chords o~ its ~w~ arc~ 14 9 15 are var~
tical, in the Figure~. ~he second portion 11 i5 then takeng
~ 7
~9~;~3~
int~oduced axially (~:lg~ 3~ ~nto part 3 and ~ilid radially
(~ig. 4) in the directlon opposite that o~ portion 109
into corrugation 2; so that the four in~e~ and outer
chord~ of the two por*ions 109 11 are parallelO Then th~
third portion 12 i~ taken, l~troduced ~xially (Fig. 5)
into part 3, and slid radially (~ig. 6~, in ~ direction at
right angles to th~t of portion~ 10, llt into co~rugatlo~
2, so that its plane~ of Join 18 9 ~9 ~lide alon~ the cor
responding portion~ of the outer chJrd~ of portlonq 10, 11,
likewise constitutl~g plane~ o~ ~oin. Finally~ th~ ~ourth
portion 13 1~ taken, lntroduced a~ially (Fig. 7) lnto part
3 and ~lid radially (Fig~ 8) in the dire¢tion op;oo~ite that
of portion 12 D into corrugation 2 9 ~0 that it~ plane~ o~
join 18, 19 slide alo~g the otha~ cor~espo~ding portion~
of the outer chords o~ portio~s 10, 11~ llk~wl~ constitu-
ting planes of join~
It wlll be noted that the a~ial intrDdUCtio~ into
part 3 of por-tions 12, 13 i~ allowed, due to the fact that
the length of their edge~ 18, 199 equal to that o~ the
2V corresponding portions o~ the out~r chord~ of portions 10,
i9 sub3tantially le88 tha~ the length o~ the inner
chord3 o~ portions 10 9 11 ~
The inner rel~forci~g rln~ 6 1~ th~ as~embled in ths
corrugation 2 9 wlth ~our annular portion~ joined alorlg two
parallel planes equidistaIlt fro~n a~is 5 o~ b011OWS 1~ the
amlular portio~ buttressl~g on vne ~nother~
A ring O, of outer di~meter substantiallr equal to
- 8 --
;37
the ln~er diameter of the tubula~ part 3, i8 then introdu-
ced ~ially, ln ord~r to block the four a~aular portions
in the corrugation 2 a~d hold r~ng 6 in positio~ of ~ei~
forcement, which is then fixed for e~ample by welding or
crimping ..
These operations are repeated for each corrugation Z.
An inner reinforcing ri~g comprising four annular
portions has been described. This i~ the simplest solution,
which is characterized by the presence of ~o~r pieces only,
of which two each haYe an inner chord and an outer chord
which are parallel, ~f the same length, and definin~ two
lateral edges perpendlcular to the~e chord~. L~t u~ recall
here that it suffice3 for one Or the annular portions cons-
tituting the rein~orcing ring to haYe two parallel or in-
wardly diverging edges in order to be able tD lntrcduce
this portion into the corrugation after the precsding ones
have been positloned.
In other words, th~ inner chord Or thi~ latter annular
portion must haYe a length equal to or greater than that
of the outer chord.
The apice~ o~ the rein~oroing ring~ 6, like those of
tha expanding corrugatlon~ 2, shown in the drawing~9 are
rou~ded. Stiffening reinforcement~ ~ay furth~r be arrang~d
around the corrugation~ 2~ ~hich comprisa at least two
p~ece~ whose inner part ~ollow~ khe shape of the corr~ga~
tions 29 and presentin~ a flat, out~r an~ular edge parallel
to the a~is 5 of the bellows 1, the piece3 of each of the
g _
outer relnforce~ents being blocked by a~ outer lockin~
ring. The stiffe~er reinforcem~nts contrlbut~ to pre~e~ti~g
the corrugations from "rising'?. The apex o~ the expandi~g
corrugations may9 moreover, also be flat.
~ inally~ outer rein~or~ing rings 7 well k~lown to the
~an skilled in the art~ may be proYided between the corru-
gations, in order al~o to withstand a hlgh in~ide pressure9
suoh outer reinforoement~ being co~po~ed Or a plurallty
of pieces ~r, preferably, being monobloc and constltuted
by the mould~ 21 the~lves u ~d in the process ~or obtai-
ning the cosrug~tivn~ by hydro~orming (~ig, 12).
The lnner r~inforcing rl~gs of th~ bellows according
to the invention en~ble the latter to with~ta~d ~ery high
outside pressures of use. By way o~ example 7 con~entional
ex~n~ n~ bellows, withst~n~ n~ only an out~ide pre~s~tre
of a few bar6, may, due to th~se inner reinforcing ringR9
, with~tand an out~ide pre~sure of ~everal hundred~ of bar~.
: It goe~ wlthout saying, a~ has already been ~mpha~iæ~d
hereinabo~e 9 that the in~ention is also applicable to a
~0 connecting sleeve provided with at least o.na a~ular groove
adaptsd to recaive an annular ga~ket, o~ d~*er~lned inner
and out~r diameter~, characte~iz~d 1~ that the gaske* com-
pri3e~ annular portion~ adapted to be introduced into th~
part of inner diameter o~ the ~leeve and ba a~mbled to
form the ga~ketg a~ well a~ mean~ ~or blocking th~ a~7ar
portion~ Df the ga~ket9 each annular porti~n having an
inner arc and an outer arc of which the ohord~ whl~h
-- 10 -
5~3~7
subtend th~m ha~e le~gthEj ~t ~h~ most equal to the ir~er
diameter of' th~ slee~e, Emd the i2~e~ chord o~ at l~a~t
on~ of the annular portio~s of th~ gaskç~t i5 a~ leas-t a~
large a~3 the outer chord thereof.
_ 11 ~
